Wood waste burner system

ABSTRACT

The present invention provides a system by means of which waste wood, as well as the fumes emitted by veneer being dried, are burned in such a manner as to basically accomplish two things, namely, provide large amounts of heat energy that was formerly wasted and, secondly, substantially reduce the emission of pollutants into the atmosphere. The system finds particular application to the lumber mill industry.

United States Patent 1191 Baardson Aug. 27, 1974 [54] WOOD WASTE BURNERSYSTEM 3,064,592 ll/l962 12116136161 110/102 x 3 0,09 3967.] ..IO [75]Inventor: Andrew Baar Beaverton, 3132:7524 6ii968 1i0i Wash- 3,675,6007/1972 Jones ll0/8 [73] Assignee: Mill Conversion (Iontractor, Inc.,

Hillsboro, Oreg. Primary ExaminerKenneth W. Sprague Attorney, Agent, orFirmWeinstein, Robbins, [22 Flled: Nov. 2, 1973 Emmy, Sam & Kay [21]Appl. No.: 412,474

[57] ABSTRACT 52 vs. C] 110/8 0, 110/8 A, 110/102 The Present inventionProvides a System y means of 51 1111. 1:1. F23g 7/00 which Waste Wood,as Well as the fumes emitted y [58] 116111 of Search 110/7 R, 7 A, 8 R,8 A, heer being dried, are burned in Such a manner as to basicallyaccomplish two things, namely, provide lar e 110/8 C, 102 g amounts ofheat energy that was formerly wasted and, [56] References Citedsecondly, substantially reduce the emission of pollut- UNITED STATES P Eants. hi $3 591? Th l i El mfifiq .Pil'gq lfi I application to thelumber mill industry. 2,614,513 l0/l952 Miller et a1. llO/7 0 3,022,7532/1962 Montgomery 110 102 X 15 Clams, 9 Drawmg Flglll'es TO ATMOSPHERE22 r ur .l' BOILER RAW WE $55 fifitifilifi 11 WOOD; METERED I COMBUSTlONBLENDlN6 SEPARATOR J 6111111111512 E CHAMBER 111m" 1 1 l.-- J H01"DAMPER 5 r QIQPEZALP NATURAL GAS SECONDARY HOT 014 PROPANE A112 6A5 6SOURCE 5011120;

DRYER FUEL METERlNG &l6NAL 21 PATENTED AUG 2 7 I974 SIEU 3 0f 5 24k M 4ZOFWDMEOU ll WOOD WASTE BURNER SYSTEM The present invention relates tothe lumber mill field in general and more particularly relates to asystem for the effective utilization of wood waste material and otherby-products of the lumber mill industry.

Lumber mills generate tons of waste wood daily and not all of it can beused for barkdust, chipboard or other commercial products. Moreparticularly, in the manufacture and processing of lumber and lumbermill products, various kinds of wood materials are developed with whichlittle can be done and which are therefore looked upon and treated aswaste. For example, in a plywood mill, the surface of the plywood isfinished by sanding the plywood and, as a result thereof, there isproduced a sander dust that is difficult to handle because it isstringy, balls up, has a tendency to bridge, is difficult to measurequantitatively, presents a fire and explosion hazard, and is generally anuisance to handle. There is also produced a substantial quantity ofwaste wood known as hog fuel, so called because it has been sized bybeing fed through a chipper or hog. In addition, there are various otherwood waste materials produced as by-products, such as bark, shavings,trimmings, sawdust, and the like. Some of the materials mentioned areusually wet or damp to one degree or another, such as the bark andsawdust, which further complicates the practical use of them.Accordingly, in the past, these materials have gone as waste wood and,in the main, have been gotten rid of by burning them in what are knownas Wigwam burners. Unfortunately, however, one of the effects of thistype of burning has been the injection or emission into the atmosphereof large amounts of pollutants, such as, smoke and ash, various kinds ofchemical emissions, uncombustible particles, and the like.

On the subject of air pollution, it should also be mentioned that in theprocess of drying veneer or green lumber, fumes are emitted from thewood that in the past, have been vented into the atmosphere. These fumesare of a combustible nature but their use as a possible heat energysource has been totally wasted. Furthermore, because of the chemicals inthe fumes, they have not only been unsightly, but also obnoxious anddeleterious in a number of respects. Considering the large volume ofthese fumes that are daily vented into the atmosphere, it will berecognized that these fumes have materially contributed to what has cometo be known as the air-pollution problem.

Needless to say, any system that could effectively utilize these wastewood products and the fumes, and use them in a manner that would reducepollution of the air we breathe, would certainly constitute asignificant step forward in the lumber mill industry. The presentinvention provides such a system, the essence of the system lying inutilizing and consuming both the waste wood and the fumes as a fuel, theheat generated thereby being used to dry the veneer or raw wood, tooperate a boiler, etc., with the remainder being fed into the atmospheredevoid of most pollutants. More particularly, in a system according tothe present invention, the waste wood is first reduced to a dry powderyform so that it can be used as a fuel. It is then fed to a rather uniquedual-chambered burner to which the fume emissions are also fed, the woodand the fumes being fired and burned in the burner to produce a very substantial amount of heat energy. The products of combustion are then fedto a unit that separates out the impurities from the hot gases, aportion of the clean hot gases then being directed to the dryer fromwhich the fumes are channeled back to the burner, as previouslymentioned. The remaining hot gases may either be vented to atmosphere orelse use-d elsewhere as an energy source, such as to operate a boilersystem or the like.

In addition to the obvious benefits to be derived from the mentionedsystem, such as the reduction in air pollution and the provision ofadditional heat energy, there are many additional advantages to begained from it. For example, propane or natural gas has customarily beenburned to provide the heat required in a dryer. The present inventionhas very materially reduced this need for propane and natural gas as afuel, with the result that very substantial savings of money can berealized from it.

It is, therefore, an object of the present invention to provide a systemthat makes effective use of waste wood and veneer or raw wood gasemissions as a fuel.

It is another object of the present invention to provide a system thatsubstantially eliminates pollution of the air that in the past cameabout as the result of the burning and drying of wood products.

It is a further object of the present invention to provide a system thatconverts wood waste to heat energy.

It is an additional object of the present invention to provide a systemthat eliminates the need for a separate fire system within a veneerdryer.

It is still another object of the present invention to provide a systemwherein veneer-dryer stack emissions are returned to a burner forcombustion as a fuel.

It is a further and additional object of the present invention toprovide a system for the lumber mill industry that controls emissions tothe atmosphere.

The novel features which are believed to be characteristic of theinvention, both as to its organization and method of operation, togetherwith further objects and advantages thereof, will be better understoodfrom the following description considered in connection with theaccompanying drawings in which an embodiment of the invention isillustrated by way of example. It is to be expressly understood,however, that the drawings are for the purpose of illustration anddescription only and are not intended as a definition of the limits ofthe invention.

FIG. 1 is a block diagram of the basic units or components of a systemaccording to the present invention;

FIG. 2 illustrates the FIG. 1 embodiment in greater detail in that itbreaks down the blocks in FIG. 1 to the apparatus included in them.

FIG. 3 is a cross-sectional view ofthe burner unit included in andplaying such a vital role in a system according to the presentinvention, and illustrates the combustion and blending chambers therein.

FIG. 4 is a front view of one of the elements included in theconstruction of the FIG. 3' burner unit;

FIG. 5 is a side view, partially in cross-section, of the wood fuelsupply and dispersion apparatus included in the construction of the FIG.3 burner unit;

FIG. 5(a) is an end-view of the FIG. 5 apparatus;

FIG. 6 is an elevation view, partially in crosssection, of a reverseflow particulate separator that constitutes one of the basic units shownin FIG. 1.

FIG. 6(a) is a cross-sectional view of the FIG. 6 apparatus taken alongthe broken line AA and in the direction of the arrows at the endsthereof; and

FIG. 7 is a block diagram showing a modification to a portion of theFIG. 1 system.

For a consideration of the invention in detail, reference is now made tothe drawings wherein, in FIG. 1, a system according to the invention isshown to basically comprise a metered wood fuel source 10 coupled on itsinput end to receive raw waste wood, such as the hog fuel, bark,shavings, etc., mentioned earlier, and coupled on its output end to aburner 11 having two chambers, namely, a combustion chamber 12 and ablending chamber 13. As will more fully be described hereinbelow, theraw waste wood is dried and ground up in wood fuel source 10 to a finepowdery form, and thereafter metered out to the burner on the basis ofneed as determined by the operating conditions of the system.

The wood fuel, along with an ample supply of air, is conveyed tocombustion chamber 12 where it is combusted or burned. However, toassure total combustion of the wood and, also, for purposes oftemperature control, an additional supply of air is fed to thecombustion chamber by secondary air source 14. It should also bementioned that in order to initially fire up the wood fuel as it entersthe combustion chamber, a certain amount of natural gas or propane needsto be supplied to the combustion chamber and this is accomplished bymeans of natural gas or propane service 15. These aspects of the systemwill, of course, be discussed in greater detail hereinbelow.

The products of combustion out of combustion chamber 12 are fed toblending chamber 13, to which are also fed certain gaseous emissionsfrom the veneer or other wood materials being dried in dryer 16. Moreparticularly, as was previously mentioned, when veneer or other woodproducts are dried, they give off gaseous materials that arecombustible. It is these gaseous emissions that are fed back to theblending chamber, as shown in the figure, when they are mixed with theproducts of combustion out of the combustion chamber and then burned.This final product of combustion then flows into a separator unit 17which functions to filter out incombustible impurities from the hotgaseous emerging from the blending chamber, thereby leaving the gasessubstantially free from these impurities.

A major portion of the hot gases out of the separator Unit is directedthrough a damper 18 to the dryer, the remainder of the gases passinginto the atmosphere. The damper controls the amount of hot gases flowingto the dryer and is operated in response to the temperature signalapplied to it via line 20, the damper thereby helping to maintain theproper temperature in the dryer. Also contributing to the temperaturecontrol of the system is a fuel metering signal that is developed in theseparator unit and fed back to metered wood fuel source 10 via line 21.As its name implies, the fuel metering signal controls or meters theamount of wood fuel that is fed to burner 11 for combustion and,therefore, controls the quantity and the temperature of these hot gases.

It should finally be mentioned in connection with the FIG. 1 system thatinstead of venting all of the remaining hot gases to atmosphere, aportion'thereof may be used in heating up a boiler 22 to produce steam,as is illustrated in the figure. It should also be mentioned thatwhatever hot gases are ultimately vented into the atmosphere aresubstantially free of any polluting ingredients, which is an additionalimprovement over the prior art.

The FIG. 1 system is presented in greater detail in FIG. 2 to whichreference is now made, the same numerical designations being used inFIG. 2 as were used in FIG. 1 wherever appropriate. As shown, the rawwaste wood is fed by means of a high pressure air line 23 to a cycloneand rotary feeder mechanism 24. The high pressure in the line forces thewaste wood toward the system and a blower (not shown) is used at the faror input end of the line to supply the needed air pressure. The cycloneand rotary feeder mechanism performs the dual function of retrieving theair or, stated differently, of separating the air from the wood, and ofthen feeding the wood to a shaker screen apparatus 25. Cyclone androtary feeder mechanism 24 is a standard piece of equipment frequentlyused in the lumber field and, therefore, its construction, operation anduse is well known to those skilled in the art. Accordingly, suffice itto say that as the air and wood enter mechanism 24, the rotary feedertherein seals off the air and thereby prevents it from continuing withthe wood to the shaker screen apparatus. The air that is thuslyseparated out is funnelled up through the center of the cyclone portionor member of mechanism 24 and out into line 26 which directs the air toa rotary feeder 27.

In shaker screen 25, the raw waste wood is first shaken out to separatethe finer wood material from the coarser pieces. In so doing, the fineparticles of wood are discharged onto rotary feeder 27 where they areagain mixed with the air coming from line 26 to be pneumaticallyconveyed to another cyclone and rotary feeder mechanism 28. As for thecoarser pieces and chunks of wood in shaker screen 25, these areconveyed by a screw conveyor device 30 to a pulverator 31 which, as itsname implies, literally hammers or pulverizes the wood into finerpieces. After pulverization, the reduced wood is conveyed back to theshaker screen unit by a second screw conveyor 32 where the process isrepeated, that is to say, the wood is shaken out with the finerparticles passing through the screen and thereafter conveyed to rotaryfeeder 27, whereas the still coarse pieces of wood are returned to thepulverator for further size reduction. This process is repeated untilall of the raw wood is ultimately reduced to a relatively fine particlesize and passed to rotary feeder 27. It should be mentioned at thispoint that shaker screen 25, as well as pulverator 31 and screwconveyors 30 and 32, are all well known in the art and, therefore, nofurther description of them is deemed necessary here.

As was previously mentioned, the air in pressure line 26 picks up thefine particles of wood in rotary feeder 27 and conveys them to cycloneand rotary feeder mechanism 28 which functions in the same manner ascyclone and rotary feeder mechanism 24. Accordingly, mechanism 28separates the air from the fine particles of wood which then pass into alarge storage bin, the air continuing down the pressure line designated34. The particles of wood stored in bin 33 constitute the wood fuelmentioned in the earlier description of FIG. 1. Coupled to the storagebin is an endless chain type of device 35 that scoops up the wood in thebottom of the bin and conveys it to a feeder device 36 that is meteredto provide the right amount of said wood fuel to burner ll. Morespecifically, the particles of wood feed to the feeder device are forceddown duct 37 by the highpressure air coming from line 34, a fan 38helping the process by pulling the air and the wood toward the burner.The metering mechanism in feeder device 36 may be a motor-driven damperor any one of a number of other commerically available mechanisms thatcan be adapted for use herein. In any event, the metering mechanism actsacts in response to a signal from controls unit 40 to either reduce orincrease the amount of wood fuel permitted to enter duct 37 according tothe needs of the system. Of course, any wood fuel conveyed to feederdevice 36 but which does not enter duct 37 is returned to storage bin33.

The wood fuel is finely divided and, therefore, is held in suspension bythe air as it moves or flows down ducts or pipes 37 and 41 toward burner11. The fuel and combustion air are introduced into combustion chamber12 in such a way that a vortex flow is established therein to aid in theprocess of combustion, additional or secondary combustion air beingsupplied to the combustion chamber by means of fan 42 and pipe 43 forthe reasons previously mentioned. As was also mentioned earlier, anatural gas or propane source is provided as a pilot light, forpre-heating purposes, and as a standby auxiliary fuel source. Theproducts of combustion out of chamber 12 are passed to blending chamber13 to which are also fed the gas emissions originating in dryer 16.These emissions are fed to the blending chamber via duct 44, a dryervent return air fan 45 being used to aid in this process by sucking thefumes from the dryer and feeding them directly into the blendingchamber.

The final products of combustion coming from the blending chamber arethen fed to separator 17 via a refractory lined duct 46 referred to as ablendalator, the function of the blendalator being to provide atransitional stage between the burner and the separator. Any combustionof the wood fuel and the emissions still remaining to be completed takesplace in the blendalator, so that the blendalator insures that theprocess of combustion is fully completed before the product thereof isfed into the separator. Separator 17, as mentioned earlier in connectionwith FIG. 1, separates or filters out the various uncombustibleimpurities that are part of the product of combustion and which may beof microscopic size, such as particles of iron and silica, with theresult that the hot gases emerging from the separator are substantiallypure. A portion of these hot gases are then fed to dryer l6 and this isdone via a duct47, the remainder of the hot gases being vented into theatmosphere through a stack 48 in which is located a damper mechanism foruse in controlling the amount of hot gas to be vented and, therefore,the amount to be channeled to the dryer.

Referring once again to controls unit 40, a thermocouple sensing elementis located in dryer 16 and this thermocouple device feeds a temperaturesignal to the control unit which, in response thereto, and by means of apneumatic signal, operates the damper in stack 48 to vary the amount ofhot gas flowing to the dryer according to its needs. Similarly, athermocouple sensing element is also located in separator l7 and thisthermocouple device likewise sends a temperature signal to the controlunit. In turn, the control unit applies an electrical signal to themetering mechanism in feeder device 36, the metering mechanism, inresponse thereto, operating to increase or decrease the amount of woodfuel out of the feeder device and, therefore, the amount of wood fuelfed to the burner. Less wood fuel will ultimately bring down thetemperature of the gases flowing from the separator to the dryer, morewood fuel having the opposite effect of course. Accordingly, by means ofthe signals and the control apparatus mentioned, both the temperature.and the volume of the gases entering the dryer can be monitored.

The construction of a burner according to the present invention is shownin detail in FIGS. 3, 4, 5 and 5(a) and, as shown therein, burner 11 isa two-stage structure in which combustion chamber 12 constitutes thefirst stage and blending chamber 13 the second stage. The burner iscylindrically-shaped and generally symetrical about its center line, thetwo chambers being lined with a refractory material, such as highalumina firebrick 50 lining the combustion chamber and castable fireclay51 around the blending chamber.

At the input to the combustion chamber is a product deflector unit,generally designated 52, comprising a burner tube 53 that is coupled atits input end to burner fan 38 and at its output end to the chamber 54in which the combustion of the wood fuel is initiated. As may be seenfrom the figures, particularly FIGS. 5 and 5(a), the burner tube iscylindrically-shaped and has a series of dispersion vanes 55 mountedperipherally around the inside of the tube near its input end, thedispersion vanes being positioned at such an angle that the combustionof combustion air and wood fuel held in suspension therein is deflectedinto a counterclockwise movement or rotation as it flows by thedispersion vanes into the burner tube. One angle that has been found tobe suitable for said purpose is the angle of 45 as formed by the planeof each vane and the center line of the burner tube. As previouslymentioned, dispersion vanes 55 are located at the input end of theburner tube.

At the output end of the burner tube and extending partially intochamber 54 is deflector apparatus, generally designated 56, thatcomprises a nosecone section 57 at its forward end and a conicaldeflector section 58 at its rearward end, the two conical sections beingseparated by a pair of concentric pipe sections 60 and 61 respectivelyused for housing and support purposes. Mounted within pipe 60 andabutting against nose-cone section 57 is a support base 62, a bolt 63extending through this support base and the nosecone section as shown inFIG. 5. A jamb nut 64 is tightly wound on the bolt so as to firmly orrigidly hold the nosecone section in place between the support base andthe nut. The entire deflector apparatus is rigidly held in position withthe aid of support brackets 65 which are mounted between pipe 60 and thewall of burner tube 53, and is best shown in FIG. 5. Thus, brackets 65centrally fix the position of pipes 60 and 61 inside the burner tube andthe pipes, in turn, aid in holding cone sections 57 and 58 in position.A backing plate 66 is mounted on and covers the base of conical section58, the junction between the plate and the conical section being filledin to form an annular concave-shaped fillet 67 that pro vides s smoothtransition from the surface of the conical section to that of the plate.As will be pointed out below, fillet 67 plays an important role in theprocess of deflecting the wood fuel product as it passes through theburner tube on the way to the combustion chamber. Finally, completingthe deflector apparatus, is a deflector ring 68 that is held in positionby the wall of burner tube 53 at the junction of conical section 58 andpipe 60, the ring being tapered or angled along its inside surface 68aso as to deflect gases and wood fuel passing through it toward conicalsection 58.

The entrance to combustion chamber 54 includes an entrance port 70through which product deflector unit 52 extends toward the combustionchamber and at the input end of which there is mounted a gas ring burner71. The gas ring burner is illustrated in both FIGS. 3 and 4 and, asshown therein, is hollow, has openings or orifices 71a along its entirecircular inner surface or periphery, and, by means of pipe 7 lb, isconnected to natural gas or propane source 15. As may also be seen fromthe figures, particularly FIG. 4, the opening or passageway through thecenter of gas burner ring 71, the opening being designated 710, isapproximately the same size or diameter as that of entrance port 70 towhich it is adjacent. Accordingly, any gases flowing through ringopening 710 thereafter flow smoothly into entrance port 70. Thesignificance of gas burner ring 71 will be pointed out hereinbelow.

As previously mentioned, chamber 54 is enclosed by a wall of firebrick50. However, between the firebrick and the outer wall of burner 11,which is also the outer wall of combustion chamber 12, the said outerwall being designated 11a, is a passageway 72 that is connected tocombustion air fan 42 by means of duct 43. Thus, in combustion chamber12, in a concentric arrangement, is chamber 54, firebrick wall 50,passageway 72 and outer burner wall 11. As has already been intimated ifnot indicated in prior discussions, air provided by air fan 42 flowsthrough passageway 72 in the direction of the arrows therein andthereafter passes through gas burner ring 71 and entrance port 70 intochamber 54. In addition to combustion air being supplied in this manner,that is to say, through the input end of chamber 54, air is alsosupplied directly to the chamber by means of channels or passagewaysthrough firebrick wall 50, that interconnects chamber 54 with passageway72, there being several such channels through the wall located atdifferent points therealong both axially and circumferentially. Thechannels shown in FIG. 3 are designated 73 and they are arranged in asortof helical path around the wall of the chamber so as to produce ahelical vortex type of flow pattern having a counterclockwise movementor rotation.

Finally, completing the construction of combustion chamber 12 is an exitport 74 located, as its name implies, at the output end of chamber 54.Exit port 74 leads to blending chamber 13 and the products of combustionleaving chamber 54 pass through port 74 on their way to the blendingchamber.

Blending chamber 13 is similar to combustion chamber 12 in severalrespects in that it also includes a chamber 75 formed by a wall ofrefractory material 51 and with entrance and exit ports 76 and 77,respectively, at its input and output ends. The blending chamber andwhat goes on inside it constitutes the second stage of burner 11 and, inthis regard, it is therefore coupled to the combustion chamber by meansof entrance port 76 which, as the figure illustrates, is incommunications with exit port 74. Coupled to this second stage is returnvent fan 45 which, as previously indicated, feeds the combustible gasesfromthe dryer to chamber 75.

Considering now the operation of burner 11 and of chambers 12 and 13therein, air under pressure with wood fuel in suspension therein is fedfirst to product deflect unit 52 where it is forced by dispersion vanes55 into a counterclockwise rotation. In view of the forward motion ofthe air and wood fuel, the counterclockwise rotation produces a helicalflow pattern as the air and wood fuel flow down burner tube 53. In thisregard, the wood is finely ground at this point and may be introducedinto the burner at speeds of approximately 5,000 feet per minute, whichis just a bit less than miles per hour. Accordingly, the air and woodenter and travel down the burner tube at a fairly high speed. Withrespect to the size of the wood particles, these will vary in size, ofcourse, but the maximum diameter of these particles will be in the orderof five sixteenths of an inch. It should also be mentioned that amongother things, dispersion vanes 55 cause the wood fuel to become evenlydispersed in the air that carries them so as to provide a uniformcross-sectional wood particle density.

The air and wood fuel combination moves down burner tube 53 in theaforementioned manner until it reaches nose cone section 57 where thecenter portion of this mass of air and wood is deflected outwardly andforced to pass through the space between pipe 61 and the burner tubewall. However, it should be emphasized that the air and wood continuesto turn in a counterclockwise direction as it moves forward through thisspace. When the air and wood reaches deflector ring 68, the outermostportion of it impinges upon deflecting surface 680 which forces itdownwardly where, together with the other air and wood passing throughthis space, it impinges upon the forward part of conical section 58. Theair and wood particles, still in a counterclockwise rotational movement,move along or follow the surface of the conical section until they reachbacking plate 66 and fillet 67 where the entire mass of air and woodfuel is smoothly channeled or turned outwardly toward wall 50 in chamber54. In the proximity of the inner surface of the wall or upon contactwith the wall itself, the wood particles are ignited due to the hightemperature at the walls surface, which temperature may be in the rangebetween 2,2002,400 F. Upon ignition, the wood particles are deflected bythe wall of chamber 54 and they then move into and through the chamberas they continue and complete the combustion process. During this periodof time, the wood continues to move in a helical path toward exit port74.

It will be recognized from what has already been said that as the airand particles of wood suspended in it emerge from the burner tube toimpinge upon conical section 58, they are joined by a mass of secondaryair introduced, as previously mentioned, via passageway 72. Secondaryair is also introduced directly into the chamber via channels 73, as wasalso previously mentioned. This secondary air serves a dual purpose,namely, it insures or guarantees that the wood fuel has sufiicient airfor complete combustion and, therefore, total comsumption although theamount of primary or conveying air is adjusted and maintained to meetthis requirement and, second, it helps to control the temperature withinthe combustion chamber to within the desired limits. Accordingly, thissecondary air plays an important role in the combustion stage of theoperation. It should finally be mentioned that gas burner ring 71 isused for start up purposes, that is to say, to bring the temperature ofthe combustion chamber to ignition range and that the natural or propanegas fed to the ring may be used to supplement the wood as a fuel shouldthat be needed.

The products of combustion obtained in combustion chamber 12 passthrough ports 74 and 76 into blending chamber 13 where, in chamber 75,these products of combustion are mixed with the combustible emissionscoming from dryer 16. It should be mentioned at this point that while aportion of the wood fuel is consumed in the combustion chamber, anotherportion continues to burn as it enters chamber 75. Accordingly, thedryers fumes or emissions are ignited in the blending chamber and burnwith the remaining wood fuel, the resultant output from the blendingchamber going through exit port 77 and into blendalator 46 where anycombustion of the wood fuel and the emissions still remaining to becompleted takes place. Thus, the blendalator is a transitional memberthat insures that the process of combustion is fully completed beforethe products thereof are fed into separator unit 117. It would beworthwhile to mention at this point that chamber 75 is larger thanchamber 54 and, therefore, that the products of combustion expand asthey enter chamber 75. It should further be mentioned that the heatgenerated in chamber 54 due to the burning of the wood fuel there ismore intense than the heat generated in chamber 75. The overall effect,therefore, is that the temperature of chamber 75 is maintained betweenl,200- l ,600" F 800-l ,000 cooler than chamber 54. As in the blendingchamber, the temperature in blendalator 46 will range between l,200-l,600 F., as will the final products of combustion passing through theblendalator on their way to the separator.

Separator unit 17 is illustrated in detail in FIGS. 6 and 6(0) and, asshown therein, is shaped like a tank that includes a tank wall 80 linedalong 'its inside surface with refractory brick 81. The floor of theseparator is also lined with this protective refractory brick. On thefloor of the separator is mounted a box 82 that extends from about thecenter of the floor to the separator wall. The box is completelyenclosed except for an opening 820 through its top wall, at that end ofthe box that is at the center of the separator floor, and a door 821) atits extremity near the separator wall. As will be seen later,uncombustible and other foreign particles enter box 82 through itsopening 82a and the accumulation of this matter is later removed fromthe box through door 8212. Located at the top of the separator, at thecenter of its roof, is an outlet duct 83. This duct iscylindrically-shaped, extends through the roof of the separator and fora short distance downwardly into the separator, and is open at its topand bottom. As will also be seen later, the clean hot gas that is ventedto atmosphere and also channelled to the dryer exits from the separatorthrough this duct 83.

Surrounding outlet duct 83 are a plurality of directional louvres 84that are mounted between top sup porting plates 85 and a bottom supportmember 86. As is indicated by the names given them, plates 85 and member86 sandwich the louvres in between them and hold the louvres rigidly inplace, As is shown in FIG. 6(a), the louvres are arranged in a circularpattern with the forward end of one louvre being parallel to and spacedfrom the rearward end of the next adjacent lou vre. Stated differently,the louvres are arranged so that air circulating on the outside of themwill be forced to pass between them to the space inside of them.

Mounted between support member 86 and opening 82a in box 82 is atruncated conical section 87 that is coupled and held to member 86 bymeans of several support brackets 88 extending from the wall of theseparator. The conical section is open at both ends, the narrow end,which is the lower end, being superimposed on opening 82a so that anyparticulate matter falling or dropping down on the inside of the conicalsection will thereby enter the box. In this regard, it should bementioned that another, much smaller, cone 89 is located and mounted atthe bottom end of conical section 87 so that the two together resemblethe letter W in the alphabet. Cone 89 is held to cone 87 by means ofbars 9 0 shown in FIG. 6(a) and as is also shown therein, the twoconical sections form an annular or ring-shaped opening between themthrough which the abovesaid particulate matter passes to box 82. Theapex or top of cone 89 is closed.

Several other features should be mentioned at this time before theoperation of the separator is described. First, the final products ofcombustion are fed to the separator by means of duct member 46 which isa con tinuation of the blendalator and, therefore, is similarlydesignated. The opening to the separator is hidden by member 46 and isnot illustrated in FlGS. 6 and 6(a) for sake of clarity. Such an openingthrough the wall of the separator can surely be visualized by anyoneskilled in the art. Second, the space between the wall of the separatorand conical section 87 has been designated 91 and it is into this space,which acts like an expansion chamber, that the products of combustionare fed. Third and last, the space between the wall of the separator andlouvres 84 have been designated 92, the space within the louvres beingdesignated 93.

Considering now the operation of separator unit 17, the hot gas enteringthe separator enters space 91 at a fairly high speed and enters in sucha manner as to move in a counterclockwise direction around conicalsection 87. Because hot gases normally rise and, furthermore, because ofthe pressure behind it, the gas entering the separator moves up alongconical section 87 in chamber 91, all the while rotating in acounterclockwise direction as it does so. Accordingly, the path followedby the gas is a helical one.

It will be noticed from FIG. 6 that as the gas rises it is confined toan ever narrower space, which the result that a Venturi effect isproduced and by the time it has reached space 92 the gas speed hasincreased and it is whirling around in a counterclockwise direction onthe outskirts of louvres 84. The gas is ultimately forced at some pointin its rotation to pass between the louvres and enter space 93 on theinside of the louvres where it continues to move in a counterclockwisedirection. Thissame gas, which previously rose, now moves down throughspace 93 and into the hollow of conical section 87, where it continuesto rotate but in an ever more confined space as it approaches the bottomor lower end of the conical section. Ultimately, the gas bottoms out, atwhich point it rises in a column at the center of conical section 87 andthen exits or vents through outlet duct 83. Thus, within the conicalsection, we have a hot gas moving downwardly in a helical path along itsinner surface and a column of this gas rising at its center. It will berecognized by those skilled in the art that cone 89 and theconfiguration formed by ill it aids in the transition from the outercolumn of gas to the inner or center column of gas. The hot gas goingthrough outlet duct 83, as previously mentioned is either channelled tothe dryer or vented to the atmosphere.

The primary function of the separator unit is to separate out variouskinds of uncombustible inorganic matter, such as particles of iron,silica, and the like, and this is done in the hollow of conical section87 by the centrifuge action produced there. The particles collect, moreor less, along the inner surface of the cone and fall or slide along itthrough opening 82a into box 82. The box is, of course, periodicallyemptied of these accumulations through door 82b.

Although a particular arrangement of the invention has been illustratedand described above by way of example, it is not intended that theinvention be limited thereto. One modification, for example, isillustrated in HO. 7 where the heat generated by the burner is primarilyintended for a boiler and only secondarily for a dryer. Accordingly, inthe FIG. 7 arrangement, the products of combustion out of blendingchamber are first fed to boiler 22 where a portion of the heat energy isused for the generation of steam. Thereafter the operatio n is maame asalreadydesc ribed, namelyfto separator unit 17 and after the separatoreither to a dryer 16 or to atmosphere. Accordingly, the invention shouldbe considered to include any and all modifications, alterations orequivalent arrangements falling within the scope of the annexed claims.

Having thus described the invention, what is claimed is:

l. A system useful in the lumber mill industry for burning the wastewoodobtained from the processing of lumber and the combustible fumesemitted from the lumber when it is dried in a dryer, said system therebyconstituting an additional source of heat energy and effectivelycombatting pollution of the atmosphere, said system comprising:apparatus for comminuting the waste wood to produce a dry powdery woodfuel; a burner having first and second chambers to which said wood fueland the fumes are respectively fed, said burner including first meansfor combusting said wood fuel in said first chamber, second means forpassing the products of said combustion to said second chamber whereinit mixes with the fumes fed thereto, and third means for combusting saidmixture in said second chamber; a separator coupled to receive theproducts of combustion out of said second chamber, said separatorincluding means that causes said products of combustion to move in sucha manner as to produce a centrifuge action that is effective to separateout impurities therefrom, whereby a hot output gas that is substantiallyfree of polluting ingredients is produced, said separator includingadditional means to channel a portion of said output gas to the dryer todry the lumber therein and to vent the remainder thereof to atmosphere;fourth means for suspending said wood fuel in a stream of air and forfeeding said air-suspended wood fuel to said first chamber; and fifthmeans for sucking the fumes out from the dryer and feeding them to saidsecond chamber.

2. The system defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner.

3. The system defined in claim 1 wherein said burner includes adeflector unit coupled at its input end to said air line and storage binto receive wood fuel suspended in air therefrom and coupled at itsoutput end to said first chamber, said deflector unit including aplurality of dispersion vanes mounted at its input end and positioned atsuch an angle as to cause said air and wood fuel to move in acounterclockwise manner as it flows therethrough toward the output endof said deflector unit, and including deflector apparatus mounted at itsoutput end to deflect said air and wood fuel outwardly toward the outerwalls of said first chamber.

4. The system defined in claim 1 wherein said means in said separatorincludes a hollow and truncated conical section that is open at its apexand base, said conical section being mounted inside said separator withits apex vertically beneath its base, a plurality of louvres mounted ina circular manner above the base of said conical section, and an outletduct mounted substantially at the center of said louvre arrangement andextending through the roof of said separator, said duct being open atits two ends; said separator including input apparatus by means of whichthe products of combustion out of said second chamber are directed in acounterclockwise movement around the apex of said conical section andupwards therealong.

5. The system defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine parti cles of wood are stored before being fed as wood fuel tosaid burner; and wherein said burner includes a deflector unit coupledat its input end to said air line and storage bin to receive wood fuelsuspended in air therefrom and coupled at its output end to said firstchamber, said deflector unit including a plurality of dispersion vanesmounted at its input end and positioned at such an angle as to causesaid air and wood fuel to move in a counterclockwise manner as it flowstherethrough toward the output end of said deflector unit, and includingdeflector apparatus mounted at its output end to deflect said air andwood fuel outwardly toward the outer walls of said first chamber.

6. The system defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for' conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said means in said separator includes a hollowand truncated conical section that is open at its apex and base, saidconical section being mounted inside said separator with its apexvertically beneath its base, a plurality of louvres mounted in acircular manner above the base of said conical section, and an outletduct mounted substantially at the center of said louvre arrangement andextending through the roof of said separator, said duct being open atits two ends; said separator including input apparatus by means of whichthe products of combustion out of said second chamber are directed in acounterclockwise movement around the apex of said conical section andupwards therealong.

7. The system defined in claim 1 wherein said burner includes adeflector unit coupled at its input end to said air line and storage binto receive wood fuel suspended in air therefrom and coupled at itsoutput end to said first chamber, said deflector unit including aplurality of dispersion vanes mounted at its input end and positioned atsuch an angle as to cause said air and wood fuel to move in acounterclockwise manner as it flows therethrough toward the output endof said deflector unit, and including deflector apparatus mounted at itsoutput end to deflect said air and wood fuel outwardly toward the outerwalls of said first chamber; and wherein said means in said separatorincludes a hollow and truncated conical section that is open at its apexand base, said conical section being mounted inside said separator withits apex vertically beneath its base, a plurality of louvres mounted ina circular manner above the base of said conical section, and an outletduct mounted substantially at the center of said louvre arrangement andextending through the roof of said separator, said duct being open atits two ends; said separator including input apparatus by means of whichthe products of combustion out of said second chamber are directed in acounterclockwise movement around the apex of said conical section andupwards therealong.

8. The system defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said burner includes a deflector unit coupledat its input end to said air line and storage bin to receive wood fuelsuspended in air therefrom and coupled at its output end to said firstchamber, said deflector unit including a plurality of dispersion vanesmounted at its input end and positioned at such an angle'as to causesaid air and wood fuel to move in a counterclockwise manner as it flowstherethrough toward the output end of said deflector unit, and includingdeflector apparatus mounted at its output end to deflect said air andwood fuel outwardly toward the outer walls of said first chamber; andwherein said means in said separator includes a hollow and truncatedconical section that is open at its apex and base, said conical sectionbeing mounted inside said separator with its apex vertically beneath itsbase, a plurality of louvres mounted in a circular manner above the baseof said conical section, and an outlet duct mounted substantially at thecenter of said louvre arrangement and extending through the roof of saidseparator, said duct being open at its two ends; said separatorincluding input apparatus by means of which the products of combustionout of said second chamber are directed in a counterclockwise movementaround the apex of said conical section and upwards therealong.

9. The system defined in claim 1 wherein said system further includes afirst network for metering the amount of wood fuel fed to said burner inaccordance with the temperature conditions in said separator, said firstnetwork including a first heat-sensitive device mounted in saidseparator for monitoring the temperature therein, said first devicebeing operable in response to said temperature conditions to produce afirst signal corresponding thereto, and a second device included in saidfourth means for metering the amount of wood fuel fed to said firstchamber in response to said first signal; and wherein said systemfurther includes a second network for metering the amount of hot gas fedto the dryer in accordance with the temperature conditions therein, saidsecond network including a second heat-sensitive device mounted in thedryer for monitoring the temperature therein, said second device beingoperable in response to said temperature conditions to produce a secondsignal corresponding thereto, and a damper device mounted between thedryer and said separator, said damper device being operable in responseto said second signal to meter the amount of hot gas flowing from saidseparator to the dryer in accordance with the temperature conditionstherein.

ill. The system defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said burner includes a deflector unit coupledat its input end to said air line and storage bin to receive wood fuelsuspended in air therefrom and coupled at its output end to said firstcham her, said deflector unit including a plurality of dispersion vanesmounted at its input end and positioned at such an angle as to causesaid air and wood fuel to move in a counterclockwise manner as it flowstherethrough toward the output end of said deflector unit, and includingdeflector apparatus mounted at its output end to deflect said air andwood fuel outwardly toward the outer walls of said first chamber; andwherein said means in said separator includes a hollow and truncatedconical section that is open at its apex and base, said conical sectionbeing mounted inside said separator with its apex vertically beneath itsbase, a plurality of louvres mounted in a circular manner above the baseof said conical section, and an outlet duct mounted substantially at thecenter of said louvre arrangement and extending through the roof of saidseparator, said duct being open at its two ends; said separatorincluding input apparatus by means of which the products of combustionout of said second chamber are directed in a counterclockwise movementaround the apex of said conical section and upwards therealong; andwherein said system further includes a first network for metering theamount of wood fuel fed to said burner in accordance with thetemperature conditions in said separator, said first network including afirst heat-sensitive device mounted in said separator for monitoring thetemperature therein, said first device being operable in response tosaid temperature conditions to produce a first signal correspondingthereto, and a second device included in said fourth means for meteringthe amount of wood fuel fed to said first chamber in response to saidfirst signal; and wherein said system further includes a second networkfor metering the amount of hot gas fed to the dryer in accordance withthe temperature conditions therein, said second network including asecond heat-sensitive device mounted in the dryer for monitoring thetemperature therein, said second device being operable in response tosaid temperature conditions to produce a second signal correspondingthereto, and a damper device mounted between the dryer and saidseparator, said damper device being operable in response to said secondsignal to meter the amount of hot gas flowing from said separator to thedryer in accordance with the temperature conditions therein.

11. The system defined in claim 3 wherein said deflector apparatusincludes first and second conical sections at its forward and rearwardends, respectively, the base of said rearward conical section includingstructure to smoothly divert said air-suspended wood fuel radiallyoutwardly toward the walls of said first chamher; and wherein saiddeflector apparatus further includes a deflector ring whose insidesurface is angled to deflect any air-suspended wood fuel coming intocontact with it toward said rearward conical section.

12. The system defined in claim 3 wherein said burner further includes asupplementary air supply arrangement to provide additional air forcombustion in said first chamber, said arrangement including a pluralityof orifices through the wall of said first chamber and located in agenerally helical path therealong, and a channel extending outside thewall of said first chamber and leading to the input end thereof, the airflowing through said orifices moving in a counterclockwise direction insaid first chamber.

13. The system defined in claim 3 wherein said burner further includes asupplementary air supply arrangement to provide additional air forcombustion in said first chamber, said arrangement including a pluralityof orifices through the wall of said first chamber and located in agenerally helical path therealong, and a channel extending outside thewall of said first chamber and leading to the input end thereof, the airflowing through said orifices moving in a counterclockwise direction insaid first chamber; and wherein said deflector apparatus includes firstand second conical sections at its forward and rearward ends,respectively, the base of said rearward conical section includingstructure to smoothly divert said air-suspended wood fuel radiallyoutwardly toward the walls of said first chamber; and wherein saiddeflector apparatus further includes a deflector ring whose insidesurfact is angled to deflect any air-suspended wood fuel coming intocontact with it toward said rearward conical section.

14. The system defined in claim 4 wherein said separator includes a boxthat is coupled through an opening therein to the apex of said conicalsection, said separator further including structural means to cause theentering hot gases to flow around and up along said conical section in acounterclockwise direction and at an ever-increasing speed, through saidlouvres and down into the hollow of said conical section to produce acentrifuge action therein that separates out incombustible ingredientsmixed with the hot gases, said ingredients falling through the apex ofsaid conical section into said box.

15. The system defined in claim 11 wherein said separator includes a boxthat is coupled through an opening therein to the apex of said conicalsection, said separator further including structural means to cause theentering hot gases to flow around and up along said conical section in acounterclockwise direction and at an ever-increasing speed, through saidlouvres and down into the hollow of said conical section to produce acentrifuge action therein that separates out incombustible ingredientsmexed with the hot gases, said ingredients falling through the apex ofsaid conical section into said box.

1. A system useful in the lumber mill industry for burning the wastewood obtained from the processing of lumber and the combustible fumesemitted from the lumber when it is dried in a dryer, said system therebyconstituting an additional source of heat energy and effectivelycombatting pollution of the atmosphere, said system comprising:apparatus for comminuting the waste wood to produce a dry powdery woodfuel; a burner having first and second chambers to which said wood fueland the fumes are respectively fed, said burner including first meansfor combusting said wood fuel in said first chamber, second means forpassing the products of said combustion to said second chamber whereinit mixes with the fumes fed thereto, and third means for combusting saidmixture in said second chamber; a separator coupled to receive theproducts of combustion out of said second chamber, said separatorincluding means that causes said products of combustion to move in sucha manner as to produce a centrifuge action that is effective to separateout impurities therefrom, whereby a hot output gas that is substantiallyfree of polluting ingredients is produced, said separator includingadditional means to channel a portion of said output gas to the dryer todry the lumber therein and to vent the remainder thereof to atmosphere;fourth means for suspending said wood fuel in a stream of air and forfeeding said air-suspended wood fuel to said first chamber; and fifthmeans for sucking the fumes out from the dryer and feeding them to saidsecond chamber.
 2. The system defined in claim 1 wherein said apparatusincludes a high-pressure air line for transporting the raw waste wood; afirst cyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner.
 3. The system defined in claim 1 wherein said burnerincludes a deflector unit coupled at its input end to said air line andstorage bin to receive wood fuel suspended in air therefrom and coupledat its output end to said first chamber, said deflector unit including aplurality of dispersion vanes mounted at its input end and positioned atsuch an angle as to cause said air and wood fuel to move in acounterclockwise manner as it flows therethrough toward the output endof said deflector unit, and including deflector apparatus mounted at itsoutput end to deflect said air and wood fuel outwardly toward the outerwalls of said first chamber.
 4. The system defined in claim 1 whereinsaid means in said separator includes a hollow and truncated conicalsection that is open at its apex and base, said conical section beingmounted inside said separator with its apex vertically beneath its base,a plurality of louvres mounted in a circular manner above the base ofsaid conical section, and an outlet duct mounted substantially at thecenter of said louvre arrangement and extending through the roof of saidseparator, said duct being open at its two ends; said separatorincluding input apparatus by means of which the products of combustionout of said second chamber are directed in a counterclockwise movementaround the apex of said conical section and upwards therealong.
 5. Thesystem defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said burner includes a deflector unit coupledat its input end to said air line and storage bin to receive wood fuelsuspended in air therefrom and coupled at its output end to said firstchamber, said deflector unit including a plurality of dispersion vanesmounted at its input end and positioned at such an angle as to causesaid air and wood fuel to move in a counterclockwise manner as it flowstheRethrough toward the output end of said deflector unit, and includingdeflector apparatus mounted at its output end to deflect said air andwood fuel outwardly toward the outer walls of said first chamber.
 6. Thesystem defined in claim 1 wherein said apparatus includes ahigh-pressure air line for transporting the raw waste wood; a firstcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafter feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said means in said separator includes a hollowand truncated conical section that is open at its apex and base, saidconical section being mounted inside said separator with its apexvertically beneath its base, a plurality of louvres mounted in acircular manner above the base of said conical section, and an outletduct mounted substantially at the center of said louvre arrangement andextending through the roof of said separator, said duct being open atits two ends; said separator including input apparatus by means of whichthe products of combustion out of said second chamber are directed in acounterclockwise movement around the apex of said conical section andupwards therealong.
 7. The system defined in claim 1 wherein said burnerincludes a deflector unit coupled at its input end to said air line andstorage bin to receive wood fuel suspended in air therefrom and coupledat its output end to said first chamber, said deflector unit including aplurality of dispersion vanes mounted at its input end and positioned atsuch an angle as to cause said air and wood fuel to move in acounterclockwise manner as it flows therethrough toward the output endof said deflector unit, and including deflector apparatus mounted at itsoutput end to deflect said air and wood fuel outwardly toward the outerwalls of said first ehamber; and wherein said means in said separatorincludes a hollow and truncated conical section that is open at its apexand base, said conical section being mounted inside said separator withits apex vertically beneath its base, a plurality of louvres mounted ina circular manner above the base of said conical section, and an outletduct mounted substantially at the center of said louvre arrangement andextending through the roof of said separator, said duct being open atits two ends; said separator including input apparatus by means of whichthe products of combustion out of said second chamber are directed in acounterclockwise movement around the apex of said conical section andupwards therealong.
 8. The system defined in claim 1 wherein saidapparatus includes a high-pressure air line for transporting the rawwaste wood; a first cyclone and rotary feeder mechanism coupled to saidair line, said cyclone and rotary feeder mechanism including first meansfor separating the air from the wood, and second means for thereafterfeeding the wood to a shaker screen mechanism; a shaker screen mechanismfor separating the fine particles of wood from the coarser pieces, saidshaker screen mechanism including third means for discharging said finewood particles into said air line for pneumatic conveyance to a secondcyclone and rotary feeder mechanism, and fourth means for conveying saidcoarse pieces of wood to a pulverator; a pulverator for comminuting saidcoarse pieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said burner includes a deflector unit coupledat its input end to said air line and storage bin to receive wood fuelsuspended in air therefrom and coupled at its output end to said firstchamber, said deflector unit including a plurality of dispersion vanesmounted at its input end and positioned at such an angle as to causesaid air and wood fuel to move in a counterclockwise manner as it flowstherethrough toward the output end of said deflector unit, and includingdeflector apparatus mounted at its output end to deflect said air andwood fuel outwardly toward the outer walls of said first chamber; andwherein said means in said separator includes a hollow and truncatedconical section that is open at its apex and base, said conical sectionbeing mounted inside said separator with its apex vertically beneath itsbase, a plurality of louvres mounted in a circular manner above the baseof said conical section, and an outlet duct mounted substantially at thecenter of said louvre arrangement and extending through the roof of saidseparator, said duct being open at its two ends; said separatorincluding input apparatus by means of which the products of combustionout of said second chamber are directed in a counterclockwise movementaround the apex of said conical section and upwards therealong.
 9. Thesystem defined in claim 1 wherein said system further includes a firstnetwork for metering the amount of wood fuel fed to said burner inaccordance with the temperature conditions in said separator, said firstnetwork including a first heat-sensitive device mounted in saidseparator for monitoring the temperature therein, said first devicebeing operable in response to said temperature conditions to produce afirst signal corresponding thereto, and a second device included in saidfourth means for metering the amount of wood fuel fed to said firstchamber in response to said first signal; and wherein said systemfurther includes a second network for metering the amount of hot gas fedto the dryer in accordance with the temperature conditions therein, saidsecond network including a second heat-sensitive device mounted in thedryer for monitoring the temperature therein, said second device beingoperable in response to said temperature conditions to produce a secondsignal corresponding thereto, and a damper device mounted between thedryer and said separator, said damper device being operable in responseto said second signal to meter the amount of hot gas flowing from saidseparator to the dryer in accordance with the temperature conditionstherein.
 10. The system defined in claim 1 wherein said apparatusincludes a high-pressure air line for transporting the raw waste wood; afirst cyclone and rotary feeder mechanism coupled to said air line, saidcyclone and rotary feeder mechanism including first means for separatingthe air from the wood, and second means for thereafTer feeding the woodto a shaker screen mechanism; a shaker screen mechanism for separatingthe fine particles of wood from the coarser pieces, said shaker screenmechanism including third means for discharging said fine wood particlesinto said air line for pneumatic conveyance to a second cyclone androtary feeder mechanism, and fourth means for conveying said coarsepieces of wood to a pulverator; a pulverator for comminuting said coarsepieces of wood to produce fine particles thereof, said pulveratorincluding fifth means for conveying said fine particles of wood back tosaid shaker screen mechanism which, in turn, discharges them by means ofsaid third means into said air line for conveyance to said secondcyclone and rotary feeder mechanism; a second cyclone and rotary feedermechanism including sixth means for separating the air from said fineparticles of wood, and seventh means for thereafter discharging saidfine particles of wood into a storage bin; and a storage bin whereinsaid fine particles of wood are stored before being fed as wood fuel tosaid burner; and wherein said burner includes a deflector unit coupledat its input end to said air line and storage bin to receive wood fuelsuspended in air therefrom and coupled at its output end to said firstchamber, said deflector unit including a plurality of dispersion vanesmounted at its input end and positioned at such an angle as to causesaid air and wood fuel to move in a counterclockwise manner as it flowstherethrough toward the output end of said deflector unit, and includingdeflector apparatus mounted at its output end to deflect said air andwood fuel outwardly toward the outer walls of said first chamber; andwherein said means in said separator includes a hollow and truncatedconical section that is open at its apex and base, said conical sectionbeing mounted inside said separator with its apex vertically beneath itsbase, a plurality of louvres mounted in a circular manner above the baseof said conical section, and an outlet duct mounted substantially at thecenter of said louvre arrangement and extending through the roof of saidseparator, said duct being open at its two ends; said separatorincluding input apparatus by means of which the products of combustionout of said second chamber are directed in a counterclockwise movementaround the apex of said conical section and upwards therealong; andwherein said system further includes a first network for metering theamount of wood fuel fed to said burner in accordance with thetemperature conditions in said separator, said first network including afirst heat-sensitive device mounted in said separator for monitoring thetemperature therein, said first device being operable in response tosaid temperature conditions to produce a first signal correspondingthereto, and a second device included in said fourth means for meteringthe amount of wood fuel fed to said first chamber in response to saidfirst signal; and wherein said system further includes a second networkfor metering the amount of hot gas fed to the dryer in accordance withthe temperature conditions therein, said second network including asecond heat-sensitive device mounted in the dryer for monitoring thetemperature therein, said second device being operable in response tosaid temperature conditions to produce a second signal correspondingthereto, and a damper device mounted between the dryer and saidseparator, said damper device being operable in response to said secondsignal to meter the amount of hot gas flowing from said separator to thedryer in accordance with the temperature conditions therein.
 11. Thesystem defined in claim 3 wherein said deflector apparatus includesfirst and second conical sections at its forward and rearward ends,respectively, the base of said rearward conical section includingstructure to smoothly divert said air-suspended wood fuel radiallyoutwardly toward the walls of said first chamber; and wherein saiddeflector apparatus further includes a defleCtor ring whose insidesurface is angled to deflect any air-suspended wood fuel coming intocontact with it toward said rearward conical section.
 12. The systemdefined in claim 3 wherein said burner further includes a supplementaryair supply arrangement to provide additional air for combustion in saidfirst chamber, said arrangement including a plurality of orificesthrough the wall of said first chamber and located in a generallyhelical path therealong, and a channel extending outside the wall ofsaid first chamber and leading to the input end thereof, the air flowingthrough said orifices moving in a counterclockwise direction in saidfirst chamber.
 13. The system defined in claim 3 wherein said burnerfurther includes a supplementary air supply arrangement to provideadditional air for combustion in said first chamber, said arrangementincluding a plurality of orifices through the wall of said first chamberand located in a generally helical path therealong, and a channelextending outside the wall of said first chamber and leading to theinput end thereof, the air flowing through said orifices moving in acounterclockwise direction in said first chamber; and wherein saiddeflector apparatus includes first and second conical sections at itsforward and rearward ends, respectively, the base of said rearwardconical section including structure to smoothly divert saidair-suspended wood fuel radially outwardly toward the walls of saidfirst chamber; and wherein said deflector apparatus further includes adeflector ring whose inside surfact is angled to deflect anyair-suspended wood fuel coming into contact with it toward said rearwardconical section.
 14. The system defined in claim 4 wherein saidseparator includes a box that is coupled through an opening therein tothe apex of said conical section, said separator further includingstructural means to cause the entering hot gases to flow around and upalong said conical section in a counterclockwise direction and at anever-increasing speed, through said louvres and down into the hollow ofsaid conical section to produce a centrifuge action therein thatseparates out incombustible ingredients mixed with the hot gases, saidingredients falling through the apex of said conical section into saidbox.
 15. The system defined in claim 11 wherein said separator includesa box that is coupled through an opening therein to the apex of saidconical section, said separator further including structural means tocause the entering hot gases to flow around and up along said conicalsection in a counterclockwise direction and at an ever-increasing speed,through said louvres and down into the hollow of said conical section toproduce a centrifuge action therein that separates out incombustibleingredients mexed with the hot gases, said ingredients falling throughthe apex of said conical section into said box.